11 



Pre-bloom application o£ endosulfan will also give good control 

 of plant bugs. In some years, such as 1979, emergence o£ over- 

 wintering adults may be strung out, and a pink application of 

 endosulfan may not have sufficient residual activity to carry 

 over and kill adults emerging after petalfall. Best results 

 will be obtained if application is made in the evening, when ad- 

 ults are most active, and if trees are well pruned to facilitate 

 pesticide coverage. 



One of the major advantages of this program is that endosulfan 

 has very little adverse effect on the principal predators of 

 spider mites and aphids in Massachusetts, and is therefore fully 

 compatible with an integrated pest management program. 



Methomyl (Lannate) Program . This program is aimed at control of 

 STLM larvae in mines and consists of 1 petalfall application of 

 methomyl (full strength) directed at 1st generation sap-feeding 

 larvae and/or 1 application of methomyl (full strength) in July 

 against 2nd generation sap-feeding larvae. Application should 

 be made only if STLM populations reach or exceed an average of 

 1 mine per leaf at petalfall or 2 mines per leaf in July. Petal- 

 fall application of methomyl will control green fruitworm and 

 leafrollers but will not control plum curculio. 



The need for precise timing and proper concentration of methomyl 

 application can not be over-stressed. Application at less than 

 full strength may give poor control. Delay of application until 

 many larvae have reached the tissue- feeding stage may not only 

 result in poor control, but more importantly, may seriously exacer- 

 bate phytotoxic effects of a variety of insecticides and fungi- 

 cides, as well as calcium chloride sprays. 



To illustrate, we are familiar with a situation in 1979 when a 

 grower applied methomyl against 2nd generation larvae after a 

 substantial number of the larvae had already entered the tissue 

 feeding stage. Control was fair, but the resulting large amount 

 of phytotoxicity from subsequent fungicide and insecticide treat- 

 ments greatly exacerbated the adverse STLM effects on premature 

 fruit ripening and fruit drop. 



Methomyl may cause severe injury to the foliage of many early 

 season apple cultivars and thus should not be applied to such 

 cultivars. Also, methomyl is a highly dangerous compound, re- 

 quiring careful use of a good respirator and gloves. 



A major disadvantage of this program is the strong toxicity of 

 methomyl to mite and aphid predators which may result in large 

 spider mite and woolly apple aphid population buildup in mid- and 

 late summer. 



